Photographic copying apparatus stripping mechanism and method



Aug. 16, 1966 E. F. STIEVENART 3,266,406

PHOTOGRAPHIC COPYING APPARATUS STRIPPING MECHANISM AND METHOD FiledSept. 25, 1965 2 Sheets-Sheet 1 INVENTOR. 3%Z6Z 17555227221272 A 16,1966 E F. STIEVENART 3,266,406

PHOTOGRAPHIC COPYING APPARATUS STRIPBING MECHANISM AND METHOD FiledSept. 23, 1963 2 Sheets-Sheet 2- United States Patent 3,266,406PHOTOGRAPHIC COPYING APPARATUS STRIP- PING MECHANISM AND METHOD EmielFrans Stievenart, Kiel-Antwerp, Belgium, assignor to GevaertPhoto-Producten N.V., Mortsel-Antwerp, Belgium, a Belgian company FiledSept. 23, 1963, Ser. No. 310,826 Claims priority, applicationNetherlands, Feb. 11, 1963, 288,817 13 Claims. (Cl. 9589) The inventionrelates generally to document copying devices and more specifically toan improved copy sheet stripping mechanism for a photographic copyingdevice of the image-transfer type.

Photographic copying devices in which an exposed light-sensitive sheetis urged in the presence of processing liquid into intimate contact withan image-receiving sheet are well known in the art. Very littleattention, however, has been given to the problem of separating by meansof mechanical instrumentalities the damp, tightly adhering sheets fromeach other.

One device which deals with this problem is disclosed in Belgian patentspecification 604,557 of General Aniline and Film Corporation in NewYork to which corresponds Canadian patent specification 656,554. In thisdevice, use is made of an image-receiving material and a lightsensitivematerial in the form of Webs which are continuously supplied fromcorresponding supply rolls. This arrangement avoids the problem of sheetseparation, since the leading edges of both webs are caused to followseparate paths when the device is loaded, which paths diverge after asufficient time of contact between the sheets has occurred. Thedisadvantages of such device, however, are a considerable waste ofmaterial, viz, the part of the web between successive copies, plus theimpossibility of producing multiple copies with a single exposedlight-sensitive material.

A second device in which sheet separation is performed is disclosed inUnited States Patents 3,020,837 and 3,062,135 of C. R. Taylor et al. Inthis device, the receiving material is applied under pressure to theprocessed light-sensitive material with its leading edge extending overa separating knife at a point which occurs immediately before theseparating knife, and therefore only a very brief time is possible forthe diffusion process to take place. Moreover, complicated means have tobe provided to permit displacement of the separate knife and aconsequential extension of the time for the diffusion, in case aplurality of copies are to be produced.

The object of the invention is to provide a copying apparatus in whichthe noted disadvantages are overcome.

Another object of the invention it to provide a stripping mechanismwhich can be mounted at the outlet of existing commonly usedphotographic copying apparatus of the image-transfer type, and isadapted to perform automatically the step of separating from each otherthe sheets leaving the apparatus.

Still another object of the invention is to provide a strippingmechanism for a copying apparatus that is of simple design andconstruction, and reliable in operation.

An advantage of an apparatus according to the present invention is thatthe device is suited for the separation of a light-sensitive materialand an image-receiving material not only when both are wetted by theprocessing liquid prior to being pressed against each other, but whenjust the light-sensitive material is wetted by the processing liquid,and even when the processing liquid necessary for performing thediffusion transfer is only present between the contacting faces of bothmaterials.

Both latter methods, wherein as a result of the small quantity ofprocessing liquid both materials or sheets Patented August 16, 1966adhere strongly to each other, have the important advantage that theproduced copies are dry or almost dry after the separation.

The device according to the present invention is particularly suited forproducing copies according to the known silver halide diffusion transferprocess.

According to this process a light-sensitive material comprising a silverhalide emulsion layer is image-wise exposed to an original and pressedagainst an image-receiving material in the presence of processingliquid, a developing agent and a silver halide complexing agent, wherebythe unexposed and undeveloped parts of the silver halide arecomplexated, and diffuse to the image-receiving material, where they areconverted into a silver image by the action of developing nuclei. Thebasic disclosure of the diffusion transfer process appears in UnitedStates Patent 2,352,014 to Rott and numerous improvements have nowappeared in the patented art, to which reference may be had if desiredfor the details involved in the practice of this process. While certainparticular materials have been found especially well adapted for use inthe apparatus of this invention, as will be hereinafter explained it hasgeneral application in the field of dilfusion transfer and is notlimited to these or any other specific materials.

The invention will be further explained by the following examples andillustrated by the accompanying drawings, in which:

FIGURE 1 is a diagrammatic side view of a copying apparatus embodyingthe principles of this invention;

FIGURE 2 is a diagrammatic top view of the copying appartus of FIG. 1,the cylinder being shown in a different position than that seen in FIG.1, certain parts being omitted for sake of clarity;

FIGURE 3 is a diagrammatic side view of a copying apparatus associatedwith a modified form of separating device according to this invention;

FIGURE .4 is an enlarged view illustrating the relative positions of theleading edges of the sheets in the modified separating device of FIG. 3;

FIGURE 5 is a diagrammatic side elevation of another form of separatingdevice for association with existing copying device, the parts thereofbeing seen in inoperative position; and

FIGURE 6 is a view of the device of FIG. 5 with the parts in operativeposition.

A cylinder or drum 10 is supported on a shaft 11 for rotation about agenerally horizontal axis. The cylinder is equipped with means 22extending transversely across its width at a point on the periphery forgripping and holding the leading edge of a sheet within a slit 21. Avariety of arrangements capable of serving as the gripping means 22 areknown in the printing art including an array of spaced pivotable fingerscarried along with the cylinder, either recessed or not, which fingerscan be elevated for the introduction of the sheet edge and thendepressed to engage the same, as well as a spring-biased clamping bladeor a wedge-actuated clamping block usually situated within a traverseslot or recess. As the details of the particular gripping means forms noessential part of this invention, it has been illustrated onlydiagrammatically.

At the bottom of the cylinder is a tank 12 for containing a supply ofprocessing fluid 13 of the type conventionally used in diffusiontransfer processes. The level of fluid supply 13 is preferablymaintained below the surface of the cylinder and an applicator roller 14is arranged partially immersed in fluid 13 with an opposite portion ofits periphery closely contiguous to the cylinder surface, the rollerbeing positively driven by means not shown at the same peripheral speedas cylinder 10. Roller 14 picks up a film of the fluid, and applies itagainst the face of the sheet carried on the cylinder surface. Otherways of coating a thin film of processing fluid upon the sheet face can,of course, be substituted and, if desired, roller 14 or its equivalentcan be so mounted as to allow displacement away from the regions of thecylinder surface not bearing a sheet. Surplus fluid can be removed by apressure or squeegee roller 15 situated beyond the applicator roller 14but within the confines of tank 12 to recover the surplus.

Placement of the light-sensitive sheet 26 on the cylinder is facilitatedby means of a feed plate or guide 18 upon which the sheet can be laidand/or advanced to insert the leading edge thereof into the grippingmeans 22 of the cylinder. Guide 18 is situated in advance of the tank ata locus on the cylinder periphery which can be varied considerably up tothe point of sheet separation to best suit spatial and designconsiderations. The light-sensitive sheet can be exposed preparatory toplacement upon the cylinder surface, e.g. by means of a known pneumaticpressure printer in which a pressure system ensures a close contactbetween the original and the light-sensitive "sheet during theillumination, a rotating tubular light source around which by means ofdriven belts the original to be duplicated is passed while in contactwith the light- 'sensitive sheet, etc.

Further along the cylinder periphery beyond squeegee roller 15 is theimage-receiving sheet feeding station formed by the pressure roller 16riding'on the surface of the cylinder and a sheet guiding passagewaydefined by guides 19 and 20. These guides are curved at the end adjacentthe cylinder surface to advance the image-receiving sheet directly tothe nip of roller 16.

To facilitate access to the leading edge of image-receiving sheet 27 foreasy ultimate separation of that sheet from sheet 26, the cylindersurface is provided at a point just preceding the gripping means with anupwardly and rearwardly inclined projection or cam 23 terminating at itsrear end as closely as possible to the leading edge of the gripped sheet26. Projection 23 can extend the full width of the cylinder or over justa portion thereof, in which event it is preferably situatedapproximately midway of the cylinder width. The radial extent of theprojection at its maximum height adjacent gripping means 22 need not beespecially great, provided it is sufiicient to raise a knife 17, to bedescribed later, clear of the leading edge of sheet 26. In the event theparticular gripping means effectively shields the edge of sheet 26, asin the case of a clamping blade overlapping the sheet edge and lyingfiat or almost so on the cylinder surface, a smoothly curved centerrecess could be substituted for projection 23 to direct the knifebeneath the edge of the top sheet and then up onto the blade. As afurther alternative, one or more elements of the gripping system, e.g.spaced gripping fingers or a transverse clamping block, can be soconfigured as to serve the purpose of projection 23.

Further along the cylinder periphery from pressure roller 16 is thesheet separating knife 17 mounted to pivot about pins 24 and lightlybiased by spring means (not shown) e.g. a torsion spring, against thecylinder surface. Alternatively, the knife blade can be naturallyresilient to permit movement of its free end. Knife 17 extends acrossthe entirety of the cylinder surface but, at least where projection 23is localized in a central region of that surface, the blade isadavantageously symmetrically tapered from a rounded end, i.e. more orless cusp-shaped, to penetrate more smoothly beneath the leading edge ofsheet 27 and thence between the sheets throughout their contacting area.One configuration very satisfactorily generally correspondscoincidentaly to the curvature of known probability curves.

It is necessary to the proper separation of the sheets according to thepresent invention that the sheet 27 be applied to the cylinder surfacein such a manner that its leading edge slightly precedes, say byone-half inch or so, the corresponding edge of sheet 26.

A crude mechanical delivering control for performing this step has beenindicated diagrammatically in FIG. 1. It includes the roller 60 which isresting on top of a stack 63 of sheets 27. The roller 60 is mounted forfree vertical movement, and is coupled by means of a flexible shaft anda magnetic clutch to a continuously turning electric motor (not shown inthe figures). When the roller 60 is turning, its peripheral speed isequal to that of the cylinder 10. The magnetic clutch is controlled bythe micro-switch 61, mounted beside the cylinder 10, and is controlledin its turn by a cam 62 rotating with cylinder 10 and so configured asfirst to close microswitch 61 when the projection 23 takes about itslowest position so as to let the roller 60 start turning for advancingthe uppermost sheet 27 of the stack 63 along a path between the guides19 and 20 which is slightly shorter than the distance on the peripheryof cylinder 10 between the projection 23 in the said lowest position andthe position as represented in FIG. 1, whereby the sheet 27 arrivesslightly leading before the sheet 26 at the cylinder periphery, andsecond, after the sheet 27 has been applied at least with its leadingpart against the projection 23 and the leading part of the wetted sheet26 on the cylinder so as to adhere thereto, to open the micro-switch forpermitting the sheet 27 to be withdrawn free from under the roller 60upon further turning of cylinder 10.

In the preceding description, all terms of orientation or operationalrelationship are with respect to the direction of cylinder rotation.

The pressure rollers 15 and 16 are mounted for free rotation on theircorresponding shafts. The surface of said pressure rollers is desirablycovered with a resilient materials. Unless the latter material yieldssufficiently to accommodate the passage of cam 23, the bearingssupporting these rollers along with roller 14 should be yieldablymounted.

Cylinder 10 is made from a hard poly(vinyl chloride). It is clear thatalso other materials which are resistant to the processing liquid may beused for the construction of the cylinder, e.g. stainless steel.

Roller 14, which with its lower part dips into the processing liquid 15has no direct contact with the periphery of the cylinder 10 exceptthrough the sheet 26. Separating knife 17 can be conveniently made outof a blade of stainless steel. As already indicated, the separatingknife covers the total width of the cylinder and rests with its frontedge on the cylinder surface. At least the free end portion of knife 11preferably extends substantially tangentially to the cylinder periphery.

The above described embodiment of the apparatus is operated as follows:

An image-Wise exposed light-sensitive sheet 26 consisting of a papersupport bearing a light-sensitive silver halide emulsion layer, isguided with its emulsion side turned downwardly over the guide member 18until its leading edge enters the slit 21 of the gripping system, whichat that moment is situated in alignment with the guide element 18. Thegripping system 22 is closed and the cylinder 10 is started to rotate.Rotation of the cylinder causes the-light-sensitive sheet 26 to wraparound the periphery of the cylinder with the emulsion side thereoffacing outwardly.

When the leading edge of the light-sensitive sheet arrives at the roller14, the film of processing liquid on the surface of the roller 14contacts the emulsion side of the sheet 26, and a meniscus forms betweenthe said sheet and the roller 14. Consequently, the light-sensitiveemulsion is wetted with the processing liquid which contains as is wellknown in the art a developing substance, a complexing agent for thesilver halide and an alkaline substance, and the development of theexposed silver halide superfluous liquid is pressed away from thelight-sensitive sheet 26 by the pressure roller 15.

A few moments later the cylinder reaches the position idicated in FIGURE1 with cam 23 just before passing beneath roller 16.

The image-receiving sheet 27 under the guidance of the guide members 19and 20, is moved forwardly by hand or by suitable means (not shown)until its leading edge contacts and rests on the inclined surface of thecam 23 on the cylinder with the extreme edge entering the nip of roller16. Thus, the image-receiving sheet 27 is slightly leadingthelight-sensitive material 26.

By means of the pressure roller 16, the image-receiving sheet is firmlypressed against the wetted light-sensitive sheet. The complexing agentpresent in the processing liquid causes the non-exposed and consequentlynon-developed silver halide to diffuse as a soluble complex from thelight-sensitive emulsion layer into the image-receiving layer, Where itis converted into a legible silver image, all as is conventional in tthediffusion transfer process.

When the cylinder 10 moves to the position illustrated in FIGURE 2, thenthe separation of the image-receiving sheet 27 from the light-sensitivesheet 26 is started. The separating knife 17 is lifted up by theslanting cam 23 and arrives with the protruding part of its edge 25under the image-receiving sheet 27. The lifting of the separating knife17 from its original position by the cam 23, causes temporarily astronger urging of the front portion of the knife 1'7 against thesurface bearing the leading edge of the image-receiving sheet 27, i.e.,the sloping cam 23. Thereby it is prevented that the'leading edge of thesheet 27 passes beneath the knife without being separated.

As the cylinder continues to rotate, the separating knife graduallypenetrates between the sheets 26 and 27 over the full width thereof.

The cam 23 prevents the front edge of the separating knife fromimpacting against the light-sensitive sheet 26 at the line where thelatter is folded and is maintained in the slit 21. Thereby it is avoidedthat the front edge of the separating knife would cut into thelight-sensitive sheet and tear it from the cylinder 10, or would gougeinto the emulsion layer of the light-sensitive sheet during the furtherrotation of the cylinder.

The image-receiving sheet 27 is delivered above the separating knife 17whereas the light-sensitive sheet 26 remains on the periphery of thecylinder 10.

Owing to the small quantity of processing liquid which is present duringthe diffusion transfer step, the imagereceiving sheet 27 is almost dryafter the separation and, is in condition for immediate use even withoutany drying after-treatment.

It has been found that excellent results can be obtained with theabove-described apparatus when a light-sensitive sheet and a receivingsheet are used, provided that the tendency of the sheets to adhere toeach other is not too strong. This tendency can be controlled byselection of the compositions of the contacting layers thereof.

In the latter respect, sheets wherein the binding agents of the toplayer of the light-sensitive sheet essentially differ from the bindingagents of the top layer of the receiving sheet are particularlyadvantageous.

Materials which are especially suited for use in apparatus according tothe present invention are disclosed in the US. patent application187,437, now abandoned, describing a process for the production ofimages according to the silver complex diffusion transfer process,comprising the use of a light-sensitive sheet, consisting of a supportcarrying a silver halide emulsion layer on top of which is applied anafter-layer of a gelatin-free water-permeable colloid, and a receivingsheet selected from the group consisting of paper, film and textilematerials; and in the U.S. patent application 300,099 describing a likeprocess comprising the use of a light-sensitive sheet bearing a silverhalide emulsion layer and a water-permeable external layer, and animage-receiving sheet comprising a support and an uppermost layercontaining a binding agent and a filler.

It is possible to further reduce the time required for producing a copyby raising the temperature of the processing liquid, as for example, byproviding an electrical heating element under the tank 12 which isthermostatically controlled, and/or by heating the sheets pressedagainst each other by means of heated rollers or a hot air blast.

After the removal of the image-receiving sheet 27, the light-sensitivesheet 26 remains on cylinder 10 until positively stripped off after, ofcourse, unlocking the gripping system 22. If one wishes to makemorecopies, the lightsensitive sheet 26 is left in place and the abovedescribed treatment is repeated each time with a new image-receivingsheet. By having the light-sensitive material remain in place, theoperations required for the production of each new copy are very muchsimplified.

The described embodiment is not limitative of the scope of theinvention. The cam 23, as well as the separating knife 17 and moreparticularly its front edge 25, may have other shapes than representedin the figures. The cam 23 may be replaced by a projection extendingover the full width of the cylinder 10 and having a slightly inclinedupper surface, as already suggested.

Moreover, the cam 23 may also accomplish the function of the grippingmechanism 22. To this end the cam 23 may be constituted by a curvedmetal clip (not shown) lying close to the periphery of the cylinder 10,and being resiliently mounted so as to enable its edge to be lifted afew millimeters for insertion of the leading edge of the light-sensitivesheet 26 there beneath. Upon releasing the clip and as the cylinder 10rotates through its cycle, the said clip holds the leading edge of sheet26, as well as lifts the separating knife 17 while passing beneath it.

The cylinder may be replaced by a cylinder segment of a lengthsufficient for supporting on its periphery the sandwich of both sheets.

The device according to the present invention is particularlyappropriate for being incorportaed in an automatic printing apparatus.

To suit this purpose, automatically operating means can be provided forthe advancing of the image-wise exposed light-sensitive sheets 2.6 onthe guide member v18 to the slit 21 of the cylinder 10, for the closingof the gripping system 22, for controlling the rotaiton cycle of thecylinder 10, and for performing the feeding of the image-receivingsheets 27 to the cam 23. Mechanisms adapted to perform this function areWell known in the printing press art and do not require specificillustration or description here. An exposure system associated with thedescribed device as well as supply stacks for the lightsensitive sheets26 and the image-receiving sheets 27 are prefer-ably used therewith. Inthat case the operation is performed as follows:

The original to be copied is introduced into the apparatus. By anappropriate sheet-feeding mechanism a light-sensitive sheet 26 isremoved from its stack and, in aligned contact with the original, ispassed along a light source. The original is ejected from the apparatuswhile the image-wise exposed sheet 26 is introduced with its lea-dingedge into the slit 2 1 of the cylinder 10 which has been rotated to theproper position and thereafter is wrapped around the cylinder. Anothersheet-feeding mechanism removes at the right moment a sheet 27 from itsstack and feeds it into the guiders 19 and 20 in tuned relation to theapproach of sheet 26. This sheet is pressed against the sheet 26 in theabove described way for a given time, and these separated againtherefrom. When a number of copies of the original is required, thecycling control device of the apparatus is set in such a Way that thelight-sensitive sheet 26 is not removed from the cylinder 10 after thecopying cycle has finished. Hence, the cylinder 10 performs anotherrevolution and a second copy is produced on a new sheet of copyingmaterial.

After the required number of copies has been delivered, the grippingsystem 22 is released and the light-sensitive sheet is removed from thecylinder by a known system, comprising for example, two rollers rotatingat relatively high speed and in opposite directions, which are urgedtemporarily against the sheet 26 and thereby rapidly unwrap the saidsheet from the periphery of the cylinder.

The application of the processing liquid may be done in other ways fromthe one explained in the foregoing example. It is thus possible topartially immerse the cylinder itself in the treating liquid. Further,the image-receiving sheet can also be moistened before it is pressed onto the light-sensitive sheet. In both these cases, the two materialsare, however, intensively wetted so that it is not possible to produce acopy which is almost dry, unless means are furnished for drying the copyobtained after the image has been formed.

It is also possible to supply each time a measured quantity of freshprocessing liquid for each copy to be produced. In that casedeterioration or oxidation by air of the processing liquid is avoided.

Finally, it is also possible to omit the tank 12 containing the treatingliquid. This can be done, for example, when the image-receiving sheetand/ or the light-sensitive sheet contains rupturable capsules filledwith processing liquid which is spread over the contacting surfaces whenpressing the light-sensitive sheet against the image-receiving sheet.The tank 12 can also be omitted when the formation of the image in theimage/receiving sheet is produced by heating the sheets pressedtogether, the sheets containing besides the substances required for theformation of the image also compounds which, upon heating, set freewater or which hydroylse whilst setting free an alkaline substance, andcontaining also hydrophilic softening agents.

Although the foregoing embodiment of the invention is preferred, thoseskilled in the art will appreciate that it requires a specially designedunit and is not very well adapted for association with existing devicesof the type in question. There is shown in FIGS. 3 and 4 a modified formof separating device which does satisfy the latter need in associationwith a typical known contacting apparatus.

The contacting apparatus, which represents the construction of a numberof known units, comprises the housing 33, the guide plates 30, theoutlet pressure roller pair 31, the tank 32 holding the processingliquid and an outlet opening 34.

The separating device comprises a plurality of continuously drivenrollers 35, 36 and 37 mounted between two upstanding supports 38, a tray39 for receiving the light-sensitive sheets and a tray 40 for receivingthe image-receiving sheets, both trays being supported by the members 38on opposite sides thereof, a sloping guide plate 43, separating knife 41vertically movable according to the dot and dash line 42. The separatingdevice is so positioned behind the copying apparatus that the slopingsupport 43 adjoins the outlet 34 of the copying apparatus.

The rollers 35, 36 and 37 rotate at a peripheral speed which is equal tothe peripheral speed of the roller pair 31. Roller 3'5 is constructed ofmetal rollers 36 and 37 contact each other and are provided with aresilient covering.

The separating knife 41 consists of a permanently curved stainless steelblade with a thickness, say, of 0.5 mm., extending the width of theroller 35. The front edge is bevelled and the configuration of the knifehas the same tapered or cusp shape as the knife of the principalembodiment. The knife is supported with its extremities disposed forsliding movement along vertical rods or slots provided on supports 38.The sliding movement is performed either by hand or by automatic means,for instance, solenoids which press the knife from its inoperativeposition (shown in FIG. 4) down to its operative position (shown in FIG.3) in which the front edge of the knife contacts over its full lengththe periphery of roller 35. The said means for moving the knife are notshown, since they are not essential for the understanding of the presentembodiment. Spring means can be placed to return the knife toinoperative position or the automatic means can incorporate such means.

The operation of the apparatus is as follows: An imagewise exposedlight-sensitive sheet 26 is .introduced, its emulsion side facingupwardly, together with an imagereceiving sheet 27, its image-receivingside facing downwardly, into the respective channels defined by theguide plates 30. The light-sensitive sheet follows the path 45; theimage-receiving sheet follows the path 46. After passing through theprocessing liquid, both sheets are squeezed between the pressure rollerpair 31 and leave same adhering to each other. In introducing thesheets, care is taken to insure that the lowermost sheet, i.e. sheet 26,slightly leads the other on emergence from the apparatus through theoutlet 34. The roller pair 31 forces the sheets upward-1y along thesloping support 43, until the leading edge of sheet 26 takes theposition as shown in FIGURE 4. At that moment the said leading edgeactuates an electrical sensing device, such as a photoelectric cell or amicroswitch, not shown, whereby the electrical circuit of the solenoidsis closed and the knife 41 is moved downwardly.

The knife deflects the leading edge of the sheet 26 so as to cause thesaid edge to move, upon further advance of the sheet, in the directionindicated by the dotted lines 47 and into tray 39. The front portion ofthe knife in operative position extends substantially tangentially ofthe periphery of the roller 35 so that the leading edge of sheet 27,which naturally tends to resist deflection, will slide over the knife,and thus will be separated from the underlying sheet. The roller pair36, 37 completes the advance of the sheets when they have left theroller pair 31. The image-receiving sheet 27 is further deflected by themetal guide fingers 48 fixed on the separating knife, so as to cause itto follow the path 49 whereby it drops after separation in the tray 40.

The operator of the modified apparatus need not wait till the sheetsleave the copying apparatus for then separating them after some seconds,as is presently the case, but may continuously feed the copyingapparatus without worrying about the separation of the sheets. Also theoperators hands will no longer be dirtied by processing liquid whenseparating the sheets, since he is only occ-upied with the dry side ofthe apparatus.

As both sheets pass through the processing liquid, a relatively greatamount of liquid is carried along which in some cases may cause thesheets in the trays 39 or 40 to adhere to each other. In such cases itmay be useful therefore to provide for a hot air blast, blowing betweenthe roller 37 and the back side of the knife 41.

The length of the sloping support 43 is selected, considering theperipheral speed of the roller pair 31, in accordance with the time thatthe sheets have to remain in contact with each other. For rather longtimes (30 secends or more) the length of the support 43 will make thedistance between the roller pairs 31 and 36, 37 exceed the distancebetween the leading and the trailing edge of the sandwich of bothsheets. Another problem which may be encountered is the buckling of thesandwich on the support 43 before the leading edge is gripped betweenthe rollers 36, 37. In both cases, another roller pair should beprovided between the said roller pairs in order to grip both sheets at asuitable intermediate point.

When the trailing edge of the sandwich of both sheets has passed beyondthe electrical sensing means, the current in the solenoids isinterrupted and the separating knife returns to its initial inoperativeposition.

Also for the alternative embodiment of the separation device, one is notlimited to the illustrated construction.

. 9 Many modifications or simplifications will be evident to one skilledin the art.

The separting knife 41 may, e.g., execute a pivoting movement instead ofthe vertical movement, which in practice will simplify the construction.Furthermore, the roller 35 may also be free turning, or in the simplestembodiment, may be replaced by a curved supporting member.

A second alternative embodiment of the separating device along the samegeneral lines as that of FIGURES 3 and 4 is shown in FIGURES 5 and 6.The said device is used in association with a contacting apparatussimilar to that represented in FIGURE 3 except that the sheets aredelivered in superposed condition'along'a horizontal part 66 of thecasing.

The separating device comprises a continuously driven roller 50, abodily movable, freely rotatable roller 51, a separating knife 52 and apresser bar 53. The separating knife and the presser bar are rigidlyconnected to each other, and both are .pivotable by means of the lever55 around shaft 54. Movable roller 51 pivots around the same shaft, andis adapted to be lifted by means of the hook-shaped member 56, fixed tothe lever 55, which engages the lever 57 carrying the roller 51 uponupward movement of lever 55.

Both rollers may have a diameter, say of mm., a length, say of 28 cm.,and can be made of stainless steel. The peripheral speed of roller 50 isequal to that of the outlet roller pair of the preceding contactingapparatus. The separating knife 52 has generally the same shape as thatrepresented in FIGURES 3 and 4. The presser bar 53 can be formed of arod of stainless steel with a diameter, say of 3.5 mm., extendingparallel to roller 50 over its full length. The operation of theapparatus is as'follows:

The image-receiving sheet 27 and light-sensitive sheet 26, both adheringto each other when leaving the contacting apparatus, are advancedtowards the separating device. The light-sensitive sheet lying below,slightly leads the other. At the moment the sheets take the position asshown in FIGURE 5, the leading edge of sheet 26 actuates an electricalsensing device, such as a microswitch, to close the electrical circuitof a mechanism, e.g. a solenoid or the like (not shown), for loweringthe lever 55. The lever 55 first assumes the position as indicated bythe: broken lines in FIGURE 6. In this position, movable roller 51 willcontact the leading edge of sheet 26 and press it against the peripheryof the roller 50 so that it will be positively advanced by roller 50.

Continued lowering of lever 55, thereafter, has two effects. The member56 releases the lever 57, so that the roller 51 remains resting underits own weight on the roller 50, and the knife 52 and the bar 53 willapproach to the periphery 'of roller 50 so as to take finally a positionas shown in FIGURE 6. Thus, the presser bar 53 presses both sheets atone place against the roller 50 while the knife 52 presses thelight-sensitive sheet 26 at a second place, located about 90 away fromthe first one, against the roller 50. .Three actions now cooperate forthe separation of the receiving sheet 27 from the lightsensitive sheet26:

First, the effect of the knife 52, resting with its bevelled edge on thesheet 26 in front of the leading edge of sheet 27, so that the edge ofthe knife will engage the sheet edge;

Second, the sharp deflection of the sheets around the periphery of theroller 50 so that the inherent inclination to resist deflection willcause the sheet 27, which is only pressed at one point against theroller, to tend to separate from the sheet 26; and

Finally, the rubbing action of the presser bar 53 on the back side ofthe sheet 27 which will give the said sheet the tendency to curl towardsthe point of application of the friction.

The roller 50, together with roller 51 resting thereon,

to those used in connection with the embodiment of FIGURES 3 and 4.

After the sheets are fully separated, the sensing device de-energizesthe electrical circuit, permitting lever 55 to return to its originalinoperative position, under the influence of a return spring or otherbiasing means, if necessary. In so moving, lever 55 also disengagesroller 51 from roller 50 by way of hook 56.

I claim:

1. In a copying device wherein image-transferring sheet material isintimately contacted by sheet-pressing means with an image-receivingsheet material and sutbsequently separated therefrom, a mechanism forseparating sheets delivered thereto with the leading edge of onematerial projecting slightly forwardly of the leading edge of the othermaterial, comprising a separating blade for penetrating between thecontacting materials, transport means for delivering the sheet materialwhile in contacting relation from said pressing means along apredetermined path to said separating blade, said transport meansincluding a generally curved surface at least in the region adjacentsaid blade, means effective at least during separation to urge saidblade towards said surface with at least the blade portion adjacent saidsurface extending generally tangentially thereof, said surface having aconfiguration such that said projecting portion of said one materialextends at an angle to the normal surface curvature as the leading edgethereof reaches said blade, said blade engaging saidangnlarly-exten-ding projecting portion of said one material anddiverting one otfsaid materials from said predetermined path whileallowing the other to proceed along said path.

2. A copy device for intimately contacting and subsequently separatingimage-tran-sfenring sheet material and image-receiving sheet material,said device comprising a transport surface movable along a circularpath, means on said surface for gripping the leading edge portion ofimage-transferring material delivered thereto, means for presentingimageareceiving material to said surface with the leading edge thereofin slightly projecting relation to the exposed forward end of saidimage-transferring material, means for pressing the two materials intointimate contact while supported on said surface, a separating bladearranged along said path forward of said pressing means, said bladebeing resiliently urged into contact with said surface and extendingangularly in the direction of movement from the locus of contact, saidsurface having a localized deformation therein underlying at least thecenter portion of the projecting end of said image receiving materialfor guiding said blade beneath said projecting end of saidimage-receiving material and over the gripped leading edge of said imagetransferring material whereby said blade strips the image-receivingmaterial while the image-transferring material passes therebeneath.

3. The device of claim 2 wherein said deformation has the form of aprojection whose surface is inclined upwardly and rearwardly relative tothe remainder of said transport surface, the forward end of saidprojection being free of overlying image-receiving material.

4. The device of claim 2 wherein said separating blade in planconfiguration tapers to a blunt surface-contacting end.

5. The device of claim 2 including means for applying processing liquidto the exposed face of said image transferring material in advance ofsaid presenting and pressing means.

6. Apparatus for pressing together and subsequently separatingimage-transferring sheet material and imagereceiving sheet materialcomprising a transport cylinder having a surface thereof of peripheralextent sufiicient to support said material, said cylinder being rotatedabout its axis, first guide means adjacent one point on the cylinderperiphery for presenting the leading edge of said image-transferringsheet material to the cylinder surface, gripping means on the cylinderfor engaging the leading edge so presented so that said material rotateswith said cylinder, second guide means adjacent a subsequent point onthe cylinder periphery for presenting the leading edge of saidimage-receiving sheet material to said cylinder in slightly leadingrelation to the gripped edge of said imagetransferring material,pressing means adjacent said second guide means for pressing saidmaterials together while supported on said surface, and a separatingknife mounted adjacent said cylinder periphery intermediate saidpressing means and said first guide means, said knife extending at anopposed angle relative to said surface and its direction of movement andurged into contact therewith over at least a portion of its edge, saidsurface having a limited discontinuity therein immediately precedingsaid gripping means at least at a transverse locus corresponding to thecontacting knife end portion, said discontinuity maintaining thecorresponding leading edge portion of said image-receiving material ingenerally displaced position relative to the underlying-surface to admitthe knife edge portion therebeneath, said discontinuity terminating inclose proximity to the gripped edge O f s-aid image-transferringmaterial and in elevated relation thereto to direct said knife edgeportion thereover.

7. A method of contacting and separating adherent sheet materialcomprising the steps of conveying one sheet material on a supportingsurface while positively gripping the leading edge of said material,applying a second sheet material on said surface in intimate contact-ingrelation to said first material with the leading end of said secondmaterial projecting slightly forwardly of the gripped leading end ofsaid first material, maintaining at least the mid-portion of saidforwardly projecting end of said second material displaced from saidsurface, and guiding a resilient separating blade beneath the displacedportion of said second material and over the gripped edge of said firstsheet material, said blade extending over the width of said materialgenerally transversely of said surface being urged into contacttherewith, and projecting in opposed angular relationship to thedirection of movement thereof.

8. A sheet stripping device for separating two superposed, intimatelycontacting sheet-s delivered with the leading edge of one sheet inleading relation to the leading edge of the other from a cont-actinguni-t having a contacting pair of delivery rollers, said devicecomprising a supp-orting surface adapted to be arranged in proximity tosaid delivery rollers to receive said sheets advanced thereby, anarcuate extension at one end of said surface, the sheet in leadingrelation contacting said surface, a resilient separating knife arrangedon the side of said sheets remote from said sheet in leading relationfor movement to and from an operative position with its edge urgedtowards said extension-from and to an inoperative position spacedtherefrom, said knife at least adjacent its edge extending generallytangentially of said extension at an opposed angle with respect thereto,said edge being urged against said extension at a point spaced from thetermination of said supporting surface a distance less than that betweenthe leading edges of said sheets, said knife being moved to operativeposition as the sheet in trailing relation approaches said extension tocontact and deflect the leading edge portion of the sheet in leadingrelation and, as said sheets continue to advance, penetratetherebet'ween to separate the same, and roller means for engaging aseparated sheet portion to continue advance of the sheets afteremergence from said pair of delivery rollers.

9. A device as in claim 8 wherein the planar surface has a lengthexceeding the length of said sheets and including positive sheet feedingmeans along said surface intermediate said pair of delivery rollers andsaid ar-cuate extension.

10. A device as in claim 9, wherein said knife extends transversely ofthe direction of advance of said sheets a distance at least equal to thewidth of the sheets and tapers from said extent to a blunt, rounded endat the edge urged into contact with said extension.

11. A device as in claim 8 including means actuated by the advance ofsaid sheets for moving said knife to operative position in timedrelation to the approach of the leading edge or said sheet in trailingrelation to said arcuate extension.

12. A sheet separating device for separating two superposed, intimatelycontacting sheets delivered with the leading edge of one sheet inleading relation to the leading edge of the other from a contacting unithaving a pair of contacting delivery rollers, said device comprising adriven first roller arranged to receive the sheets as delivered, atleast one second roller cooperating with said driven roller, said secondroller being normally spaced away from said first roller and adapted tobe depressed into contact therewith to positively grip and advance thesheet in leading relation, a presser bar movable to wrap said sheetsaround an arc of said first roller in advance of the locus of contactbetween said rollers while the same grip said sheet in leading relation,and a resilient separating knife movable towards said first roller tocontact the leading portion of the sheet in leading relation along thearc formed by said presser bar, at least the edge portion of said knifeextending generally tangentially of said are at an opposed angle withrespect to the advance of said sheet to penetrate between said sheetsand separate the same as said sheet in leading relation is positivelyadvanced.

13. The device of claim 12, wherein said presser bar and said knife arecarried on a common support for simultaneous movement.

References Cited by the Examiner UNITED STATES PATENTS NORTON ANSHER,Primary Examiner.

C. B. PRICE, Assistant Examiner.

Stievenart et a1 -89

1. IN A COPYING DEVICE WHEREIN IMAGE-TRANSFERRING SHEET MATERIAL ISINTIMATELY CONTACTED BY SHEET-PRESSING MEANS WITH AN IMAGE-RECEIVINGSHEET MATERIAL AND SUBSEQUENTLY SEPARATED THEREFROM, A MECHANISM FORSEPARATING SHEETS DELIVERED THERETO WITH THE LEADING EDGE OF ONEMATERIAL PROJECTING SLIGHTLY FORWARDLY OF THE LEADING EDGE OF THE OTHERMATERIAL, COMPRISING A SEPARATING BLADE FOR PENETRATING BETWEEN THECONTACTING MATERIALS, TRANSPORT MEANS FOR DELIVERING THE SHEET MATERIALWHILE IN CONTACTING RELATION FROM SAID PRESSING MEANS ALONG APREDETERMINED PATH TO SAID SEPARATING BLADE, SAID TRANSPORT MEANSINCLUDING A GENERALLY VURVED SURFACE AT LEAST IN THE REGION ADJACENTSAID BLADE, MEANS EFFECTIVE AT LEAST DURING SEPARATION TO URGE SAIDBLADE TOWARDS SAID SURFACE WITH AT LEAST THE BLADE